365129eae1
Algorithm Rewrite of the core int32/avx2 implementation for (1) higher speed and (2) reduced memory consumption. Stack allocation is now at most a few kilobytes, even for gigantic arrays. Internally, the sorting algorithm is now mostly bitonic to simplify indexing, although odd-even speedups are still applied when convenient. Lanes are complemented to take the down-up decision out of the inner loops. As in previous djbsort versions, data is sorted first in vector lanes and then transposed for final merges, reducing the overall number of vector permutations. Unlike previous versions, transposition is done in-place. The transposition in this version is bit-reversal on the outer 6 bits (bottom 3 bits and the top 3 bits), but leaves intermediate bits alone. Non-power-of-2 array sizes are handled by an extra, more traditional, merge step. Sizes 2, 3, 4, 5, 6, 7, 8, 16, 32 are now special-cased. Non-power-of-2 sizes below 256 are padded to the next power of 2. Portable implementations: The out-of-place int32/portable1 and int32/portable2 implementations are now gone; the in-place int32/portable3 and int32/portable4 implementations remain. C API float32_sort is now supported. The arithmetic in the reduction from float32 to int32 is int32 31-bit right shift, uint32 1-bit right shift, xor; this is slightly more efficient than the reduction from float32 to uint32 from 2001 Herf. Compiling Tests now have more variation (without much slowdown): the uint32 test cases now deviate from int32 in more than the sign; float32 uses floating-point numbers that aren't integers; int32 does more loops for small cases, and some larger cases. Internals API for 2-input sorting is now MINMAX macro operating on two inputs in place. Better inline assembly from Jason Donenfeld for 2-input sorting: more flexibility in compiler's register allocation. The package version number is now automatically copied to version.c as the implementation version number for implementations that don't provide version.c. Verification minmax now supports more peephole optimizations for complemented bitonic sorting and for padding: xor(s,xor(s,t)) ⇒ t; xor(-1,s) ⇒ invert(s); Reverse(Reverse(s)) ⇒ s; signedmin(invert(s),invert(t)) ⇒ invert(signedmax(s,t)); signedmax(invert(s),invert(t)) ⇒ invert(signedmin(s,t)); invert(s)[high:low] ⇒ invert(s[high:low]); s[bits-1:0] ⇒ s; s[high:low][high2:low2] ⇒ s[high2+low:low2+low]; Concat(...)[high:low] ⇒ ...[high-pos:low-pos] when possible; Reverse(s)[high:low] ⇒ Reverse(s[...]) when possible; eliminate signedmin/signedmax when one input is the minimum or maximum constant. verifymany now includes the implementation version number on verified lines.
5 lines
111 B
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5 lines
111 B
Text
include/djbsort_cpucycles.h
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include/float32_sort.h
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include/int32_sort.h
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include/uint32_sort.h
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lib/libdjbsort.a
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